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Full text of "Growing buckwheat."

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Agriculture 
Canada 

Research Direction generale 
Branch de la recherche 



Technical bulletin 1 986-7E 




Growing buckwheat 




1886-1986 



The map on the cover has dots representing 
Agriculture Canada research establishments. 

ONE HUNDRED YEARS OF PROGRESS 

The year 1 986 is the centennial of the Research Branch, Agriculture Canada. 

On 2 June 1 886, The Experimental Farm Station Act received Royal Assent. The passage of this 
legislation marked the creation of the first five experimental farms located at Nappan, Nova 
Scotia; Ottawa, Ontario; Brandon, Manitoba; Indian Head, Saskatchewan (then called the North- 
West Territories); and Agassiz, British Columbia. From this beginning has grown the current sys- 
tem of over forty research establishments that stretch from St. John's West, Newfoundland, to 
Saanichton, British Columbia. 

The original experimental farms were established to serve the farming community and assist the 
Canadian agricultural industry during its early development. Today, the Research Branch con- 
tinues to search for new technology that will ensure the development and maintenance of a com- 
petitive agri-food industry. 

Research programs focus on soil management, crop and animal productivity, protection and re- 
source utilization, biotechnology, and food processing and quality. 



Growing buckwheat 



C.G. CAMPBELL and G.H. GUBBELS 
Research Station, Agriculture Canada 
Morden, Manitoba 



Research Branch 
Agriculture Canada 
1986 



Copies of this publication are available from 

Research Station 

Research Branch 

Agriculture Canada 

P.O. Box 3001 

Morden, Manitoba 

ROG 1J0 

Produced by Research Program Service 

© Minister of Supply and Services Canada 1 986 
Cat. No A-54-8/1986-7E 
ISBN 0-662-14789-8 

Egalement disponible en francais sous le titre Culture du sarrasin 



Growing buckwheat 

C. G. Campbell and G. H. Gubbels 
Research Station, Morden, Manitoba 



Introduction 



Buckwheat has become an important special crop in Canada. Plantings have 
averaged about 46,377 ha each year during the past decade. Manitoba produces 
the majority of buckwheat in Canada with a 10-year average of 37,635 ha. 

Although buckwheat is not a true cereal, it is usually classed with the 
cereals because the crop and its grain are handled in the same way as a 
cereal. 

The buckwheat described in this publication is common buckwheat, Fagopyrum 
esculentum Moench. A related species, tartary buckwheat, _F. tataricum (L.) 
L.J. Gaertn. , is cultivated in Eastern Canada but is a noxious weed in Western 
Canada. Wild buckwheat, Polygonum convolvulus L. , a common weed, is more 
distantly related. These related species do not cross with common buckwheat. 

Buckwheat is grown mainly to produce seed for human consumption. It is 
also used as a green manure crop, as a smother crop to crowd out weeds, and as 
a source of buckwheat honey. About two-thirds of the Canadian buckwheat crop 
is exported, with Japan being the largest customer. The Japanese grind most 
of the buckwheat into flour for making noodles and they use the hulls from the 
seed for stuffing pillows. 

The buckwheat plant 

The buckwheat plant is a broad-leaved, erect annual with a single main 
stem and several branches. It has a shallow taproot system with several 
branched lateral roots. The root system is less extensive than those of the 
true cereal grain plants. The limited root system and large leaf surface 
combine to make the plant susceptible to wilting during periods of moisture 
stress. 

The stem is usually smooth, grooved, succulent, and hollow. It varies 
from green to red and turns brown as it approaches maturity. The dark green 
leaves are heart shaped. 

Buckwheat has an indeterminate flowering habit. Dense clusters of showy 
flowers bloom at the ends of branches or on short pedicels arising from the 
axils of the leaves. The flowers are usually white, but pink ones 
occasionally occur. The flowers have five petal-like sepals and occur in two 
main types. The pin type has long styles and short stamens, and the thrum 
type has short styles and long stamens. The plants usually do not set seed 
with their own pollen. Consequently, pollination must occur between plants of 
different flower types and is usually done by insects such as bees. 



- 2 - 



Botanically the seed is called an achene. Its hull is triangular and 
varies from brown through gray to black in color. The groat, which is the 
tissue inside the hull, is covered by a thin layer of material. This layer is 
green when the seed is first harvested and turns reddish brown as the seed 
ages. 

Adaptation 

Buckwheat grows well during warm weather, but it is sensitive to high 
temperatures and hot, dry winds, especially when moisture is scarce. These 
conditions during flowering can cause flower blasting, which reduces seed set 
and yield. Buckwheat is susceptible to frost and can be severely damaged by 
late spring or early fall frost. Therefore, seeding should be delayed until 
the danger of spring frost is past. Because of its short growing season, only 
10-12 weeks, buckwheat is sometimes used as a catch crop in an emergency. It 
can be grown when wet weather or a late spring delays the seeding of cereal 
crops or when another crop has failed because of severe weed infestation or 
poor stands. Buckwheat must be seeded early enough, however, so that the 
seeds are well formed and nearly mature before fall frost kills the plant. 

Although buckwheat is best adapted to well-drained sand or silt loam 
soils, it grows well under a wide range of soil conditions. It is often grown 
on heavier soils but should not be seeded on poorly drained, saturated soils. 
When buckwheat is subjected to high winds or heavy rains or is grown on very 
fertile soils, it also tends to lodge. 

Place in the rotation 

When you select a field for buckwheat, avoid fields previously seeded with 
wheat, oats, or barley because cereal grains from volunteer plants are 
difficult to separate from buckwheat. Buckwheat should follow these three 
cereals only if the land can be tilled in the fall and again in the spring to 
germinate volunteer seeds and eliminate resulting seedlings. Never seed 
buckwheat on rapeseed, mustard, or sunflower stubble because volunteers from 
these crops are difficult to control. 

Carefully select a suitable crop to follow buckwheat in the rotation. 
Because buckwheat seeds shatter easily, volunteer growth often occurs in the 
field the next year. To control volunteer growth of buckwheat in succeeding 
crops, apply herbicides when the buckwheat is in the seedling stage. The crop 
following buckwheat must be resistant to the specific herbicide applied. 
Consult your agricultural representative for the latest herbicide 
recommendations for your area and choose your next crop accordingly. 

As a precaution, wait at least 2 years between buckwheat crops in a 
rotation; although at present disease is not a problem in buckwheat, this 
practice reduces the risk of disease organisms increasing. It also minimizes 
the mixing of buckwheat cultivars that occurs when volunteers from a previous 
crop are allowed to grow with the new crop. 



- 3 - 



Cultivars 

The cultivars Mancan, Manor, and Tokyo are licensed for production in 
Canada. All three are classed as midseason types. Although a limited amount 
of nonlicensed buckwheat is also produced, growers should use Pedigreed seed 
to ensure top quality and high production. 

Mancan buckwheat was developed at the Research Station, Morden, Man. It 
has large seeds, thick stems, and large leaves. The flowers are white, 
although some pink ones do occur. It has dark brown to black seeds, some of 
which have wings that are paperlike extensions of the hull. 

Manor buckwheat was also developed at the Research Station, Morden, Man. 
It has large seeds, thick stems, and large leaves, similar to Mancan. The 
flowers are white and the seeds are dark brown to black. Manor has a more 
concentrated flowering period than does Mancan. 

Tokyo is a combination of two lines developed from a Japanese introduction 
by the Research Station, Ottawa, Ont. Its leaves, stems, and seeds are 
smaller than Mancan or Manor and the seed is dark brown. It is a 
vigorous-growing cultivar. 

A quantity of nonlicensed buckwheat is also produced each year. It is 
usually a mixture of Japanese and Silverhull types that produces small seed 
and highly variable plant and seed characteristics. 

Mancan and Manor are preferred in the Japanese market because of their 
large seeds and high percentage of groat. Canadian buckwheat breeders are 
presently developing earlier, larger seeded cultivars with reduced height for 
improved lodging resistance. These are expected to replace the smaller seeded 
types that are less desirable in the export market. 

Seedbed preparation 

Prepare the seedbed for effective control of weeds,, conservation of 
moisture, and provision of firm soil near the surface. Although shallow 
tillage in early spring may not be necessary on light-textured soils, it 
promotes early germination of weed seeds on heavier soils. A second tillage 
just before seeding kills these weeds. To minimize moisture loss, maintain a 
firm seedbed, and reduce chances of bringing new weed seeds to the surface, 
keep tillage shallow. Harrowing should then leave the field ready for seeding 
with a grain drill. Alternately, seeding with a discer allows you to combine 
the three final operations into one. 

Date, rate, and depth of seeding 

It is important to remember that buckwheat is susceptible to frost in late 
spring and early fall. Tests at the Morden Research Station have shown that 
yields are highest when the crop is seeded soon after the risk of frost has 
passed but they decline sharply if seeding is delayed. For example, yields 
from buckwheat seeded at the beginning of June were as much as double 



- 4 - 



those from seedings made at the end of June. When the crop is used as an 
alternate to summerf allow, seedings as late as early July sometimes give 
satisfactory returns. However, because buckwheat requires 10-12 weeks to 
produce an acceptable crop, late seeding is risky in areas where frosts are 
common in early fall. 

A seeding rate of 40-55 kg/ha is recommended. The higher rates are 
suggested for fields where weeds may be a problem. A high plant population 
helps the crop to compete with weeds. Buckwheat plants branch extensively and 
are often capable of compensating for thin stands. Therefore, if poor 
emergence occurs, delay turning the crop down until you are sure the plants 
will not produce an adequate canopy. 

Seed 4-6 cm deep. Although shallow seeding is desirable for rapid 
emergence, it is important to place the seed in moist soil. Use a 
conventional grain drill or a discer for seeding. Seed treatment is not 
necessary in the prairies. 

Fertilizers 

When soil fertility is low, buckwheat responds well to fertilizer. A 
buckwheat crop that yields 1600 kg/ha removes 47 kg nitrogen, 22 kg phosphorus 
(P2O5), and 40 kg potassium (K2°) from the soil for each hectare planted. 
Have your soil tested and fertilize accordingly. Too much nitrogen encourages 
vegetative growth and promotes lodging. In most soils, the application of 
phosphorus is likely to produce a consistent increase in yield. For best 
results, sideband the phosphorus 2.5 cm to the side and 2.5 cm below the 
seed. If fertilizer is applied with the seed, do not exceed 7 kg/ha for 
nitrogen and 20 kg/ha for phosphorus (P2O5) to avoid injury to the seedlings. 
Higher amounts of nitrogen and phosphorus and all potassium should be placed 
away from the seed. 

For current information on fertilizer recommendations in each province, 
refer to the publications that are available on request from either the 
provincial or federal departments of agriculture. 

Weed control 

Most weeds are controlled by carefully preparing the seedbed. In good 
stands of buckwheat the seedlings compete strongly and smother weeds. In thin 
stands, further controls may be needed if a severe weed problem is 
anticipated. For the latest recommendations in weed control, consult your 
local agricultural representative. 

Pollination 

Buckwheat is naturally cross-pollinated, usually by insects. Honey bees 
and leaf cutter bees are effective pollinators. Besides increasing seed set 
and seed yield, honey bees return an added value in the honey they produce. 
Buckwheat honey is darker than No. 1 White Honey and has a distinctive flavor. 



- 5 - 



Flowering begins 5 or 6 weeks after the seed is sown and continues for at 
least a month, often until frost. An arrangement with an apiarist can help 
maximize pollination of the crop to your mutual benefit. If you advise the 

apiarist where you intend to seed buckwheat, colonies can be placed to 
maximize buckwheat yield and honey production and to avoid undesirable 
mixtures of honey from different crops. 

Insects and diseases 

Problems with insects and diseases are not common. Cutworms and aphids 
can cause damage, and occasionally control becomes necessary. Aster yellows 
sometimes occurs, but it seldom causes extensive losses. Recently, downy 
mildew, which occurs in humid weather, has been identified as causing foliar 
lesions that may reduce yield. If a severe insect or disease problem 
develops, consult your local agricultural representative for the most 
effective control. 

Harvesting and threshing 

Buckwheat is usually swathed, then harvested with a combine after the 
plants and seeds have dried. Because buckwheat has an indeterminate growth 
habit, flowers, green seed, and mature seed are present on the plant at the 
same time. Often much of the total yield is produced in the cooler weather 
just before frost, and early swathing can reduce yield. If plants 
are flowering profusely and there is a heavy set of green seeds developing, it 
is best to delay swathing. Generally, if flowering is almost finished, 
swathing should be done when 75% of the seeds have turned brown. If there is 
severe frost damage, swath the crop promptly. Seeds shatter easily once the 
plants dry, and lodging can occur soon after severe frost. However, if the 
frost was light, there may be many green seeds that will still develop and 
swathing may be delayed until the usual time. Swathing in the early morning 
when dew is present or in damp weather helps keep losses caused by shattered 
seed to a minimum. The reel speed should correspond to ground speed to reduce 
shattering. Careful handling is very important because shattering losses of 
up to 22% have been recorded on experimental plots. 

Combine the crop when the seed in the swath contains less than 16% 
moisture. In order to reduce shattering, reduce the pickup speed to match the 
ground speed. A draper type of pickup causes less shattering than a drum 
type. To minimize seed breakage, reduce the cylinder speed initially to about 
600-800 revolutions per minute and set the concaves to 13-16 mm in the front 
and 9 mm in the rear. If breakage is excessive, further reduce the cylinder 
speed or increase the concave clearance. Set the upper sieve initially at 16 
mm and the lower sieve at 8 mm. The lower sieve can then be opened gradually 
to the setting that does not allow excessive foreign material to pass 
through. This procedure ensures that the amount of seed entering the return 
is minimized, thereby minimizing seed breakage. 

Usually buckwheat yields 800-1000 kg/ha, although yields of 2000 kg/ha and 
higher have been produced under favorable conditions in Manitoba. 



- 6 



Storage 

A moisture content of 16% or less is necessary for safe storage of 
buckwheat. If the seed requires drying, the temperature should not exceed 
43°C. This temperature limit applies to seed for both seeding and commercial 
use. Do not store grain for sale the next year, because the Japanese market 
demands buckwheat from new crops only. Mixing seed from old and new crops 
reduces marketability. Mixtures of old and new seed can be easily detected 
because the light green color of the layer just under the hull in freshly 
harvested seed gradually changes to reddish brown during storage. 

Marketing 

Buckwheat is marketed according to grades established under the Canada 
Grain Act, as shown in Table 1. Most of the buckwheat crop is exported and 
the rest is used domestically. The export market has recently undergone many 
changes, with Japan now providing the largest market for Canadian buckwheat. 
Future propects look good for the buckwheat grower. However, for an assured 
market and a guaranteed price, be sure to obtain a sales contract in advance. 

Uses 

Buckwheat is most commonly grown as a grain for human consumption. It has 
also been grown as a livestock and poultry feed, a green manure crop, a 
companion crop, a smother crop, and as a source of dark buckwheat honey. 
Although the grain and straw can be used for livestock feed, the total 
nutritive value is lower than that of cereals. 

Consumption of buckwheat in Canada accounts for about one-third of the 
crop. It is used in pancake mixes, breakfast cereals, poultry dressing, and 
certain breads and ethnic dishes. 

In Japan, buckwheat flour is mixed with wheat flour in the manufacture of 
buckwheat noodles. The buckwheat flour must be milled from fresh seed to have 
the desired flavor. Therefore, the Japanese market does not accept mixtures 
of buckwheat seed from old and new crops. The Japanese use the hulls from the 
seeds for stuffing pillows. 

The protein in buckwheat flour is of exceptionally high quality because it 
contains a considerable amount of lysine, a protein component deficient in 
cereal products. Buckwheat is rated as one of the best sources of high 
biological value protein in the plant kingdom. 





1. Pin flower with taller female and shorter male 
parts. 

2. Thrum flower with shorter female and taller 
male parts. 

3. Flower cluster showing stages of maturity. 

4. Flowering is almost finished and 75% of the 
seeds have turned brown. 

5. Dehulled seed: (a) buckwheat from a new 
crop is light green, (b) buckwheat from an old 
crop is reddish brown. 



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